AQ - - by hcj


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                   STATE OF IDAHO
                   DEPARTMENT OF
                   ENVIRONMENTAL QUALITY

1410 North Hilton • Boise, ID 83706 • (208) 373-0502                                             C. L. “Butch” Otter, Governor
                                                                                                        Toni Hardesty, Director

                           Small Wood-Fired Boiler Permit to Construct
                                     Application Checklist
This checklist is designed to aid the applicant in submitting a complete permit to construct application for a
wood-fired boiler with a rated input capacity of 1.0 million Btu/hr and less than 10.0 million Btu/hr that will be
located at a minor facility. Combustors of less than 1.0 million Btu/hr are not required to obtain a permit to
construct (IDAPA

Applications for a permit to construct will be processed in accordance with the Procedure for Issuing Permits
(IDAPA, which specifies the amount of time for DEQ processing of permit applications, as follows:

        Thirty (30) days to review the application for completeness.
        Sixty (60) days (after completeness determination) to prepare the permit for issuance or to prepare the
         proposed permit for public comment if a public comment opportunity is requested.
        If a public comment period is requested, DEQ must issue or deny the permit within 45 days of the start
         of the 30-day public comment period, unless the Director determines that additional time is required to
         address comments received.

I.   Actions Needed Before Submitting Application

         Refer to the Rule. Read the Permit to Construct requirements contained in IDAPA,
         Rules for the Control of Air Pollution in Idaho.

         The Rules are available on DEQ’s website (go to

         Consult with DEQ Representatives. It is recommended that the applicant consult with DEQ to discuss
         application requirements before submitting the permit to construct application. This step often saves the
         applicant time and effort. The consultation can be in person or on the phone. Contact DEQ’s Air Permit
         Hotline at 1-877-5PERMIT to schedule the consultation.

         Submit a Dispersion Modeling Protocol. (Dispersion modeling is sometimes called ambient air quality
         modeling.) It is suggested that a dispersion modeling protocol be submitted to DEQ at least two (2)
         weeks before the permit to construct application is submitted. Contact DEQ’s Air Permit Hotline at
         1-877-5PERMIT for information about the protocol.

         A dispersion modeling protocol checklist and template are available on DEQ’s website (go to, under Checklists).

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II. Application Content
       Application content should be prepared using the checklist below. The checklist is based on the
       requirements contained in IDAPA (Application Procedures).
       Apply for a Permit to Construct. Complete and submit the following forms from DEQ’s website at, under Application Forms:
           Cover Sheet (Form CS)
           General Information (Form GI)
           General Emission Unit (Form EUO)
           Plot Plan (Form PP)
           Modeling Information Workbook (Form MI)

       Permit to Construct Application Fee. A $1,000 permit to construct application fee must be submitted
       when the original application is submitted. Refer to IDAPA Note that a permit to construct
       processing fee will be required to be paid prior to the permit issuance. Refer to IDAPA

       Process Description and Process Flow Diagram. The process or processes for which the construction
       permit is requested must be described in sufficient detail and clarity such that a member of the general
       public not familiar with air quality can clearly understand the proposed project. A process flow diagram is
       required that includes the boiler and fuel feeding system; the description provided must describe the
       boiler’s design (e.g., single chamber, dual chamber, combustion air, supplemental fuel, etc.) and how
       the fuel feeding system operates and is controlled.

       Equipment List. All equipment for which the construction permit is requested must be described in detail.
       Such description includes, but is not limited to, manufacturer, model number or other descriptor, serial
       number, maximum combustion rate, proposed combustion rate, maximum heat input capacity, stack
       height, stack diameter, stack gas flowrate, stack gas temperature, etc. All equipment for which the
       construction permit is requested must be clearly labeled on the process flow diagram.

       Emission Inventory. Submit the uncontrolled emission inventory that does not consider restrictions on
       emissions such as air pollution control equipment, hours of operation, or limiting wood combustion rates
       below the design combustion rate capacity of the burner. Also submit a controlled emission inventory
       that does consider operational restrictions. Any physical or operational limit on emissions given in the
       application will become a limitation in the permit to construct.

       Applicants must use the most representative emission data available for the combustor type that is
       proposed to be installed. When source specific emissions test data are not available, the Environmental
       Protection Agency’s AP-42 emissions factors are often used to estimate emissions. Listed below is the
       emission data that DEQ knows is available:

       Messersmith Single Combustion Chamber - Council, Idaho (March, 2007) and Vermont Source Test
       Data (April, 1996)

       Chiptec Dual Combustion Chamber - Vermont Source Test Data (April, 1996)

       EPA, AP-42 Compilation of emission factors

       The Vermont source test data may found at the following link:

       EPA’s compilation of emission factors (AP-42) may be found at the following link:

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A summary of the Council, Idaho source test data for a Messersmith single combustion chamber unit is
attached to this application form. This test data indicates that very complete combustion occurred
during the test. In fact, if carbon monoxide emission factors are used as an indication of combustion
efficiency the wood fired Messersmith single combustion chamber unit was more efficient than a natural
gas fired boiler. If this source test data is used to represent emissions from your proposed single
chamber combustion unit ongoing monitoring will be required in the permit to assure complete
combustion is maintained during operation of the emission unit. Monitoring may consist of continuous
temperature monitoring, carbon monoxide monitoring or other operating parameters that the applicant
demonstrates assures complete combustion. (The Vermont emission test data for the single chamber
Messersmith combustor indicates normal combustion efficiency, use of the Vermont data instead of the
Council data in obtaining a permit will result in a permit being issued with less stringent operating and
monitoring requirements that are designed to assure that highly efficient combustion occurs.)

Emission Inventory and Modeled Ambient Concentration for All Regulated Air Pollutants. All proposed
emission limits and modeled ambient concentrations must demonstrate compliance with all applicable
air quality rules and regulations. Regulated air pollutants include criteria air pollutants, toxic air
pollutants listed pursuant to IDAPA and 586, and hazardous air pollutants listed pursuant
to Section 112 of the 1990 Clean Air Act Amendments.

Go to to see the original list of hazardous air pollutants.
Describe in detail how the proposed emissions limits and modeled ambient concentrations demonstrate
compliance with each applicable air quality rule and regulation. Calculations, assumptions, and
documentation for emissions estimates must include sufficient detail so DEQ can verify the validity of
the emissions estimates. When estimating emissions, thoroughly document the source of the emissions
factors that were used to estimate emissions. Be sure to use the most representative data available.
Contact DEQ to determine what emissions data are known to be available for use in these estimates.

Toxic Air Pollutant Compliance Demonstration. Complete and submit the Toxic Air Pollutant
Preconstruction Application Completeness Checklist.

(The checklist can be found at

If toxic air pollutants prove to be a concern while preparing the application, or if T-RACT is pursued,
  contact DEQ prior to submitting the application. DEQ has established an Air Permitting Hotline to
  provide assistance to those preparing permit applications. The telephone number for the Air Permitting
  Hotline is 1-877-5PERMIT.

Particulate Matter Grain Loading. Demonstrate compliance with the fuel burning equipment particulate
matter grain loading standard (0.200 gr/dscf @ 8% O2,, corrected for altitude). Refer to IDAPA & 680.

Procedures Manual. Prepare and submit a procedures manual that details how the combustor will be
operated and monitored to assure combustion efficiency is maintained. Combustion efficiency can be
influenced by combustion temperature, combustion air, fuel type, fuel moisture content, fuel feeding
procedures and idle or pilot operating conditions. At a minimum the procedures manual is expected to
address each of these. The procedures manual purpose is to assure that wood is combusted under
optimum conditions (i.e. temperature and combustion air) and to describe the ongoing monitoring that
will be undertaken to assure these conditions are maintained.

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What Can an Applicant do to Facilitate the Permitting Process?

      Select a consultant that is familiar with the Idaho DEQ air quality rules and has demonstrated technical
       competence in preparing air permit applications.

      Propose a clean-burning, low-emission combustion chamber unit. Source testing conducted in Vermont
       showed that a single combustion chamber burner emitted more than 7 times the amount of
       formaldehyde, and 22% more particulate than a dual chamber combustion unit.

      If a dual combustion chamber is proposed, the Toxic-Reasonably Available Control Technology (T-
       RACT) provisions of the rules may be satisfied. Contact DEQ prior to submitting an application
       requesting T-RACT, contact information follows.

      If toxic air pollutants prove to be a concern while preparing the application, or if T-RACT is pursued,
       contact DEQ prior to submitting the application. DEQ has established an Air Permitting Hotline to
       provide assistance to those preparing permit applications. The telephone number for the Air Permitting
       Hotline is 1-877-5PERMIT.

      Submit an air dispersion modeling protocol for review prior to submitting an application. The application
       may require the use of modeling tools to demonstrate compliance with the air quality standards.
       Contact DEQ to discuss the modeling protocol early in the application process.

      Contact DEQ prior to submitting an application to discuss the emission factors that will be used to
       estimate emissions. DEQ has an Air Quality Permitting Hotline to provide assistance to applicants
       before they submit applications. The Hotline number is 1-877-5PERMIT. Use the Small Wood-Fired
       Boiler Permit to Construct Application Checklist that DEQ has developed to assist you in preparing an

      Use the most representative emission data available for the type of combustor that is proposed for use.

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              Council School Emissions Test Results - March 27, 28, 29, 2007
               Wood-Fired Messersmith Single Chamber Combustion Unit
                               2.46 MMBtu/hr Heat Input
                                                     High Fire            Normal Fire
                                                     Emissions            Emissions
                         Pollutant                   (lb/MMBtu)           (lb/MMBtu)
                         PM                                 0.442                0.57
                         PM 2.5                             0.129               0.228
                         NOx                                 0.41                0.22
                         CO                                  0.04                0.05
                         Arsenic                          7.41E-06            1.69E-06
                         Cadmium                          4.88E-05            1.22E-05
                         Chromium                         5.24E-05            1.19E-05
                         Nickel                           4.91E-05            1.17E-05
                         Benzo(ghi)perylene (PAH)         5.04E-07
                         Fluoranthene (PAH)               2.62E-06            2.86E-06
                         Napththalene (PAH)               3.80E-06            9.30E-06
                         Phenanthrene (PAH)               2.43E-06            3.91E-06
                         Pyrene (PAH)                     2.99E-06            6.39E-06
                         Formaldehyde                     9.00E-04            1.00E-03

These emissions data are presented for high fire and normal fire. DEQ has reviewed the Council emissions
data and determined which emissions factors should be used for permitting purposes, as follows:
     For pollutants that have a short term standard (24 hour) the highest value should be used.
     For pollutants that have a long term standard (Annual) the average of the high fire and normal fire
        should be used.

            Recommended Emission Factors for Use in Preparing an Air Permit
                Application Based on the Council School Emissions Test
                                                                     Emissions Factor
                            Pollutant                                  (lb/MMBtu)
                            PM                                              0.57
                            NOx                                             0.315
                            CO                                              0.05
                            Arsenic                                       4.55E-06
                            Cadmium                                       3.05E-05
                            Chromium                                      5.24E-05
                            Chromium +VI                                  5.37E-06
                            Nickel                                        3.04E-05
                            Napththalene (PAH)                            9.30E-06
                            Formaldehyde                                  9.50E-04

               1) 16.7% of Chromium is hexavalent - EPA AP-42 section 1.6 Wood Residue Combustion In
                   Boilers, September 2003 (the recommended emission factor is an average of the Council
                   Test high fire and low fire chromium x 0.167)

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What Do the Council School Emissions Data Indicate?

Review of the Council School emissions test results show that the unit displayed very complete combustion
during the emissions test. In fact, the data show that combustion of wood was more complete during the
emissions test than may be normally expected from combusting natural gas (as determined by comparing
carbon monoxide emissions data).

If the applicant chooses the Council School emissions data to represent emissions from their proposed single
chamber emissions unit, the air permit will require a means of assuring that complete combustion is achieved
during ongoing operations because incomplete combustion leads to formation of air pollutants such as
formaldehyde (see the graph below for the relationship between carbon monoxide emissions and formaldehyde
emissions from wood-fired combustion units). Complete combustion may be assured by monitoring carbon
monoxide or temperature. A likely requirement would be a continuous temperature monitoring and recording
device to assure the combustion unit is maintained at a high enough temperature to assure complete

                                                CO vs. Formaldehyde


   Formaldehyde lb/MMBtu





                                      0   0.5           1             1.5       2   2.5
                                                            CO lb/MMBtu

Carbon monoxide (CO) and formaldehyde emissions from wood-fired combustion units. Data used
to establish the graph is from: the March, 2007 Council, Idaho Source test; April, EPA AP-42
emission factors; and1996 Vermont source test.


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